Soft tissues, such as ligaments, tendons, and muscles, are attached to a large portion of the human skeleton. In particular, many ligaments and tendons are attached to the bones which form joints, such as shoulder and knee joints. A variety of injuries and conditions require attachment or reattachment of soft tissue to bone. For example, when otherwise healthy tissue has been torn away from a bone, surgery is often required to reattach the tissue to the bone to allow healing and natural reattachment to occur.
A number of devices and methods have been developed to attach soft tissue to bone. These include screws, staples, cement, suture anchors, and sutures alone. Some of the more successful methods involve use of a suture anchor to attach a suture to the bone, and tying the suture in a manner that holds the tissue in close proximity to the bone.
The tissue may be attached to the bone during open surgery, or during closed (e.g., arthroscopic) surgical procedures. Closed surgical procedures can be preferred since they are less invasive and are less likely to cause patient trauma. In a closed surgical procedure, the surgeon performs diagnostic and therapeutic procedures at the surgical site through small incisions, called portals, using instruments specially designed for this purpose. One problem encountered in the less invasive, closed surgical procedures is that the surgeon has significantly less room to perform the required manipulations at the surgical site. Thus, devices and methods are needed which will allow a surgeon to effectively and easily attach tissue to bone in the small spaces provided by less invasive surgical procedures.
Proper attachment of soft tissue requires that it be placed in the anatomically correct position to promote optimal healing. Conventional methods for attaching soft tissue to bone have typically used anchors through which sutures can be pulled to draw a piece of soft tissue attached to the suture into proximity of the bone surface after the anchor is inserted in a predrilled bone cavity. Such methods then require the free end or ends of the suture to be tied off to hold the soft tissue in place. This requires a high degree of dexterity from the surgeon, and it can be difficult or impossible to maintain ideal tension on the suture while tying the knot, as there is a tendency for the suture to slip.
There is thus a need for improved devices and methods for attaching soft tissue to bone which reduce the tendency for the suture or anchor to pull out of the bone and which allow the suture to be tensioned without slipping and without requiring knot tying.